#include <iostream>
using namespace std;
void main ()
{
int sum=0;
cout<<"vvedite 1 chelo(nachlo diapozona)\n";
int  n;
cin>>n;
cout<<"vvedite 2 chelo (konez diapozona)\n";
int a;
cin>>a;
	while(n<=a)
	{
		if(n%2!=0)
		{ 
		sum=sum+n;
		}
	n++;
	}
cout<<"symma nechotnix chisel = "<<sum;
}